Fix heli spawn/landing at FOB/FARP

Fixes https://github.com/dcs-liberation/dcs_liberation/issues/2719.

(cherry picked from commit 34de855b8f889b72406c101d0cea385988e24bf9)
(cherry picked from commit b41ef0ab13fad0969eef321f71377ae6eb800d36)

changelog.md

@@ -5,6 +5,7 @@
 * **[Data]** Fixed unit ID for the KS-19 AAA. KS-19 would not previously generate correctly in missions. A new game is required for this fix to take effect.
 * **[Flight Planning]** Automatic flight planning will no longer accidentally plan a recovery tanker instead of a theater refueling package. This fixes a potential crash during mission generation when opfor plans a refueling task at a sunk carrier. You'll need to skip the current turn to force opfor to replan their flights to get the fix.
 * **[Mission Generation]** Using heliports (airports without any runways) will no longer cause mission generation to fail.
+* **[Mission Generation]** Prevent helicopters from spawning into collisions at FARPs when more than one flight uses the same FARP.
 
 # 6.1.0
 

game/missiongenerator/aircraft/aircraftgenerator.py

@@ -26,6 +26,7 @@ from game.settings import Settings
 from game.theater.controlpoint import (
     Airfield,
     ControlPoint,
+    Fob,
 )
 from game.unitmap import UnitMap
 from .aircraftpainter import AircraftPainter
@@ -180,4 +181,12 @@ class AircraftGenerator:
                 self.unit_map,
             ).configure()
         )
+
+        wpt = group.waypoint("LANDING")
+        if flight.is_helo and isinstance(flight.arrival, Fob) and wpt:
+            hpad = self.helipads[flight.arrival].units.pop(0)
+            wpt.helipad_id = hpad.id
+            wpt.link_unit = hpad.id
+            self.helipads[flight.arrival].units.append(hpad)
+
         return group

game/missiongenerator/aircraft/flightgroupspawner.py

@@ -230,16 +230,22 @@ class FlightGroupSpawner:
     def _generate_at_cp_helipad(self, name: str, cp: ControlPoint) -> FlyingGroup[Any]:
         try:
             helipad = self.helipads[cp]
-        except IndexError as ex:
+        except IndexError:
             raise NoParkingSlotError()
 
         group = self._generate_at_group(name, helipad)
 
-        if self.start_type is not StartType.COLD:
+        if self.start_type is StartType.WARM:
             group.points[0].type = "TakeOffParkingHot"
+        hpad = helipad.units[0]
         for i in range(self.flight.count):
-            group.units[i].position = helipad.units[i].position
-            group.units[i].heading = helipad.units[i].heading
+            group.units[i].position = hpad.position
+            group.units[i].heading = hpad.heading
+            # pydcs has just `parking_id = None`, so mypy thinks str is invalid. Ought
+            # to fix pydcs, but that's not the kind of change we want to pull into the
+            # 6.1 branch, and frankly we should probably just improve pydcs's handling
+            # of FARPs instead.
+            group.units[i].parking_id = str(i + 1)  # type: ignore
         return group
 
     def dcs_start_type(self) -> DcsStartType: